Voltage regulator



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. ITJ QUPPL) l v I V 5" J SUPPLY Dec. 8,194.2. L."H. HILL I I VOLTAGE REGULATOR Original Filed Jan.i15. 1941 a Sheets-Shet :av

Reissued Dec. 8, 1942 Leland H. Hill, Wauwatosa,

lis-Chalmers Manufacturing Company,

Wis, assignor to Al- Mil- I waukee, Wis, a corporation of Delaware Original No. 2,278,261, dated March 31, 1942, Se-

rial No. 374,433,

for reissue September 3,

13 Claims.

This invention relates in general to voltage regulators and control systems therefor and relates particularly to regulators in which two inductively related windings ar utilized to add or subtract a voltage to or from a circuit and in which such added or subtracted volta e is automatically varied by an electromechanical operator.

In prior art regulating apparatus of the above type, where one winding is connected across a circuit .and th other winding is connected to January 15, 1941. Application 1942, Serial No. 457,203

add or subtract a variable voltage to or from 1 such circuit, the maximum safe current value of at least one of the windings, is a limiting factor of the apparatus. Such apparatus, when regulating the voltage of a load circuit to a predetermined value independent ofchanges in the supply voltage, is designed for a limited range of supply voltage variation within which the desired regulation of the load voltages will be maintained. In these prior art regulators, limiting devices were applied which prevented movement of the regulator beyond the point at which the maximum safe current value in the windings was obtained. I

It has been found desirable to provide for an increase in the permissible safe load current in voltage regulator windings in order to avoid addition of another regulator to take care of increased load on th regulated circuit. Some prior art induction regulators utilize a two-part series connected winding, the sections of which may be reconnected in multiple, thereby doubling the permissible maximum safe load current but halving the range of regulation.

It is desirable to have an adjustment availabl without the necessity of disconnecting and reconnecting the regulator windings, thereby necessitating discontinuance of service by the regulator. It is also desirable to utilize a small increase in maximum'safe current valu with an accompanying small decrease in regulating range.

It has been found that such adjustment can be obtained by adjusting the action of the limiting means of the regulator operator. By utilizing a simple mechanical adjustment, easily available on the outside of the regulator, indication of the maximum safe current setting and the supply voltage range'can also be obtained. Also by-using a simple mechanical adjustment such adjustment can easily be made responsive to the load current or to the winding oil temperature or to a combination of both.

It is therefore anobject of the present invention to provide a regulator and control system and apparatus therefor which utilizes any or all of the above advantages, and avoids any or all of the above disadvantages of the prior art regulators.

It is also an object of this invention to provide an adjustable limiting means for a regulator operator, such as is shown in the drawings and described herein, whereby changes in the maximum safe current value of the regulator windings may be simply and easily eiiected either manually or in response to given. conditions.

Other objects and advantages of the invention will be apparent from the following description when read in connection with the accompanying drawings, in which:

Fig. l is a schematic diagram of a regulating system embodying the present invention;

Fig. 2 is a front elevation of a limit switch and position indicator construction which may be utilized in the regulating system of Fig. 1;

Fig. 3 is an end view of the structure in Fig. 2;

Figs. 4,5, 6, 'I and 8 are detail views of various elements of the regulating apparatus shown in Figs. 2 and 3;

Figs. 9 and 11 are front and end elevational views of a modified form of the invention shown in Figs. Stand 3; and

Fig. 10 is a schematic diagram showing a modifled form of the invention shown in Fig. 1.

As shown in Fig. 1, a load circuit '38 has its voltage regulated to a predetermined value independent of changes in the voltage of a supply circuit 39, by means of the two inductively related windings 35 and 36. For convenience, the regulator is shown as a step regulator, however, the system is as applicable to an induction regulatoror to any other type of regulator involving two induction windings, one of which, such as 35, is an exciting winding and is connected across the circuit and the other, such as 36, is a series winding and is connected so as to add or subtract a voltage to or from the circuit.

The turns of the series Winding 36 connected into the circuit, are varied in number by the dial switch, shown generally at 31, and in direction by the reversing switch 50. These switches are operated by means of a motor 40 energized from awinding M and controlled by a primary relay shown generally at 42, which is responsive to the voltage across the load circuit 38. The coil of the primary relay 42 is shown connected to a winding 43 which with the windto the shaft 68 so as to rotate therewith.

40 at either extreme position of the regulator.

The limit switch operator 1| has a pivotal movement about a stub shaft 12 to operate either limitswitch 53 or 54. Movement of the operator 1| is caused by adjustable members 51 or 58 which are adjustably affixed to rotate with the The position indiposition indicator shaft 68. cator shaft 68 is driven from the shaftof the dial switch 31 by any suitable means such as a chain 84.

The limit switch and position indicator struc-' ture is shown more clearly in Figs. 2 to v, in-- elusive. A shaft 54 has bearings in an insulating frame member 58 and a metal frame member 13. is driven from the dial switch 31 by the chain 84. A pinion 61 pinned to the shaft 64 drives a gear 59 pinned to the position indicator shaft 68. A pointer is pinned to the shaft 68 and acts in conjunction with a scale 14 to indicate the position of the dial switch movable contacts 46 and 41. The scale" may be supported on. the frame member 13 as by the bolts 85. On the other end of the shaft 68 is a hub 86 pinned The hub 85 supports the members 51 and 58 which, as shown in Figs. 4, 5, 6 and 7, are provided with curved slots 59 so that these members A sprocket 85 is pinned to the shaft 54 andare angularly adjustable about the 'shaft 68. 1

These members 51 and 58 have upturnedends 62 which cooperate ,with the upper end of the limit switch "operator 1I to move the same about 1 its pivot 12; The member 51 also has a guiding slot BI and these members are clamped by means of cap screws 60 in any one of five positions relative to the hub 86. I

With the apparatus in the position shown in Fig. 2, which is the position of the-dial switch shown in Fig. 1 and indicated in Fig. 8, movement of the regulator to the number 1 position will cause a clockwise movement of the shaft 68 as viewed in Fig. 2. Movement of this shaft will cause the upturned nd 52 of the adjustable member 51 to move-the upper end of the operator 1| toward the left as viewed in Fig. 2. thus opening the motor energizing circuit by operation of the limit switch 53. As a space saving measure, the shaft 64 rotates in a hole' 15 in the operator H which is large enough to permit operating movement 'of the operator 1| about its pivot 12. A cap screw 80 'holds the operator 1| on the shaft 12.

The winding is designed for a predetermined maximum safe current value which, for example, may be 200 amperes. The winding 35 is designed for double this value. If it is desired to utilize this regulator on .an increased loadof setting of the limit switches.

range of movement of the dial switch 31 is cut down fifty percent.

In any inductively related windings, the ampere turns of the primary winding are equal to the ampere turns of the secondary winding. By

decreasing the regulating range, that is, by de creasing the number of turns of the winding 35, available for regulation, to one-half, the current therein-may be doubled and the number of ampere turns therein maintained constant, but with a doubled current value. If the ampere turns in winding 36am maintained constant, the ampere turns of winding 35 are similarly maintained constant and vas the number of turns is not varied, the current therein will remain within the designed maximum safe current value.

This change can be easily and simply made without taking the regulator out of service, as would be necessary if the winding connections were to be changed. It also permits increasing the current rating of the regulator in small steps with consequent small decrease in regulating range. Often the increase in system load, necessitating an increase in regulator current rating, may be only 10 to 30% and if this can b effected with only a 10 to 30% decrease in'regulating range, better regulation can be obtained.

The limit switch adjustment is shown as having five positions; that is, five difierent,h0les 53 in'which the cap screws 58 may be seated. These positions as shown would correspond to permissible current ratingsiinthe example above given) of 200, 229, 267, 320 and 400 amperes and corresponding regulating ranges of i10%, i i :6%%. and :5%. A greater number of positions may be had by increasing the number of holes 53, with a consequent finer adjustment of current ratings and regulating range. The above figures and the number of steps shown in the drawing are merely examples of conditions and adjustments that have been found desirable.

In Figs. 9 and 11, a modification of the structure shown in Figs. 2 and 3 is illustrated whereby The above is obtained by cutting away a circular section from the position indicator scale 1| so that the position of the adjustable limit switch members 51 and 58 can readily be seen. As shown in Fig. 11, these members may have scale markings thereon or maximum safe current value such as 200, 300 and 400 and accompanying markings of 10, 7.5 and 5 depicting the range The cap screws 60 may have a distinguishing color and will indicate the position of the adjustable members. The cap screws 60 may easily be, reached through the position indicator scale 14 by means of a screw driver, and the adjustment made from the front of the regulator.

In the construction above described, manual adjustment of the limit switches has been contemplated, perhaps as a result of an alarm showing overloading of the regulator windings. In Fig. 10 a modification of this construction is shown whereby the adjustment of members 18 may be made responsive to the load current. The members 16 are illustrated as beingguided for movement on a circle 81 by action of bimetallic members "which are aflixed to the shaft 88. Heatingcoils 18 energized from a current transformer 19 are utilized to actuate the bimetallic members 11 in accordance with the amount of load current flowing. These bimetallic members 11 ma also be responsive to the temperature of oil in which the regulating windings are immersed by immersion in this same oil. An oil level hasbeen indicated in Fig. 10.

If the current in the load circuit 38' exceeds a predetermined value for which the windings are turn the regulator to a point within such range.

For example, with the apparatus in the position shown in Fig. 10, a heating of the bimetallic members 11 will move the left hand member 15 so that the upturned end 62 thereof moves away from the right hand adjustable member. Such movement will cause the member H to move, in a counterclockwise direction as viewed in the drawing, about its pivot I! thus actuating the contact 53 to open the circuit to the motor through the upper contact of the primary relay 53. This action prevents the regulator from going.in the raise direction.

Movement of the bimetallic member 15 as described above may decrease the range of regulation below-the point corresponding to that at which the dial switch stands. If such is the case, the member II will be forced further in a counterclockwise direction until the switch 53 closes the contacts 56 thus energizing the motor 40 to run the regulator in a lower direction until the limit position of the new range isobtained, at which time the back contacts 55 will be opened. Similar back contacts 55 are provided for the limit switch 5| which operates at the other end oi! the voltage range. The dial switch, windings and control system for the regulator of Fig. 10 may otherwise be the same as 'that shown in Fig. 1.

The invention has been illustrated by means of a so-called step regulatorin which a series winding 36 is tapped and of which the number of turns, added or subtracted to or from the voltage of supply 39, is varied. The windings and 36 are as well illustrative of the windings of a so-called induction regulator, one winding of which is connected across the circuit and the other winding of which is connected in series with the circuit and the inductive relation between the two windings varied to obtain the desired regulation.

Although but several embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various modifications and changes may be made therein without departing from the spirit of the invention or from the scope of the appended.

claims.

It is claimed and desired to secure by Letters Patent:

1. In combination, a supply circuit, a load circuit connected to said supply circuit, electr'oresponsive means for regulating the voltage of said load circuit to a predetermined value independent of variations of the voltage of said supply circuit within a predetermined range, said regulating means having a maximum safe current value, means for limiting operation of said regulating means, and means for varying saidlimiting means whereby said maximum safe current value and said range 01' variation are varied in relatively small increments.

2. In combination, a supply circuit, a load circuit connected to said supply circuit, electroresponsive means for regulating the voltage of said load circuit to a predetermined value independent of variations of the voltage of said supply circuit within a predetermined range, said regulating means having a maximum safe current value, and means operatively responsive to the current in one of said circuits for increasing said maximum safe current value.

, 3. ,In combination, a supply circuit, a load circuit connected to said supply circuitjelectroresponsive means for regulating the voltage of said load circuit to a predetermined value independent of variations of the voltage of said supply circuit within a predetermined range, said regu- 4 lating means having a maximum safe current value, and means operatively responsive to the currentin said load circuit for increasing said maximum .safe current value.

4. In combination, a supply circuit, a load circuit connected to said supply circuit, electroresponsive means for regulating the voltage of said load circuit to a predetermined value independent of variations of the voltage of said supply circuit within a predetermined range, said regulating means comprising a winding having a maximum safe current value, and means operatively responsive to the temperature of said winding for increasing said maximum safe current value.

5. In combination, a supply circuit, a load circuit connected to said supply circuit, electroresponsive means for regulating the voltage of said load circuit to a predetermined value independent of variations of the voltage of said supply circuit within a predetermined range, said regulating means comprising a winding immersed in insulating fluid, said winding having a maximum safe current value, and means operatively responsive to the temperature of said fluid for increasing said maximum safe current value.

6. In combination, a supply circuit, a load circuit connected to said supply circuit, electroresponsive means for regulating the voltage of said load circuit to a predetermined value independent of variations of the voltage of said sup ply circuit within a predetermined range, said regulating means comprising a winding immersed in insulating fluid, said winding having a. maximum safe current value, and means operatively responsive to the temperature of said fluid and the current in one of said circuits for increasing said maximum safe current value.

7. In a control system for regulating the voltage of a load circuit to a predetermined value independent of variation of the voltage of a supply circuit, a primary relay responsive to the voltage of said load circuit, means responsive to operation of said primary relay for varying the volt age of said load circuit relative to the voltage of said supply circuit, said means comprising a winding having a maximum safe current value, means for limiting the range of operation of said voltage varying means, and. means remote from said winding for adiusting said range limiting means while maintaining said regulator operatively connected to said load and supply circuits whereby the maximum safe current value of said winding isvaried without removing said regulator from service.

8. In a control system for regulating the voltage, of a load circuit to a predetermined value independent of variation of the voltage of a sup ply circuit, a: primary relay responsive to the voltage of said load circuit, means responsive to operation of said primary relay for varying the voltage of said load circuit relative to the voltage of said supply circuit, said meanscomprising a winding having a maximum safe current value,

means for limiting the range of operation 01' said voltage varying means, and means for adjusting said range limiting means whereby the maximum safe current value of said winding is varied, and means for indicating the maximum safe current value of said winding.

voltage varying means, and means for adjusting said rangelimiting means whereby the maximum 9. In a control system for regulating the voltage of a load circuit to a predetermined value independent of variation of the voltage of a supply circuit, a primary relay responsive to the voltage of said load circuit, means responsive to, operation of said primary relay for varying the voltage of said load circuit relative to the voltage of said supply circuit, said means comprising a winding having a maximum sate current value, means for limiting the range or operation of said voltage varying means, and means for adjusting said range limiting means whereby the maximum safe current value of said winding is varied, and

means for indicating said range of operation of means for limiting the range or operation of said sate current value of said winding isvaried, and means for indicating said range and said maximum safe current value.

11. In a voltage regulator, two inductively related windings, means for varying the operative relation of said windings to regulate the voltage of a circuit, said means comprising a motor, a limit switch in circuit with said motor, and means responsive to an overload condition of one or said windings for adjusting the operation of said switch. l

12. In a control system for regulating the voltage of a load circuit to a predetermined value independent of variation of the voltage of a sup ply circuit, a primary relay responsive to the voltage of said load circuit, means responsive to operation of said primary relay for varying the voltage of said load circuit relative to the voltage of said supply circuit, said means comprising a winding having a maximum safe current value, means for limiting the range or operational said voltage varying means, and means responsive to an overload condition of said winding for adlusting said range limiting means.

13. In a control system for regulating the voltage or a load circuit to a predetermined value independent of variation oi the voltage of a supply circuit, two inductively related windings one or which is connected to be energized iromsaid supply circuit and the other of which is connected to add or subtract a voltage to or from said load circuit, means for varying said added or subtracted voltage, means for limiting the range of operation or said varying means, and means for adjusting said limiting means to vary the maximum safe current value of said windings in increments corresponding to increments of the order of one to five per cent of said load circuit voltage.

LELAND H. HILL. 

